Re: [PATCH v2] mmc: tmio: move runtime PM enablement to the driver implementations

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Niklas,

On Fri, May 17, 2019 at 1:03 AM Niklas Söderlund
<niklas.soderlund@ragnatech.se> wrote:
> On 2019-05-08 11:03:05 +0200, Geert Uytterhoeven wrote:
> > On Mon, Apr 15, 2019 at 1:10 PM Wolfram Sang <wsa@the-dreams.de> wrote:
> > > On Thu, Apr 11, 2019 at 12:22:40AM +0200, Niklas Söderlund wrote:
> > > > Both the Renesas and Uniphier implementations perform actions which
> > > > affect runtime PM before calling into the core tmio_mmc_host_probe()

> > > > which enabled runtime PM. Move pm_runtime_enable() from the core and
> > > > tmio_mmc_host_probe() into each drivers probe() so it can be called
> > > > before any clocks or other resources are switched on.
> > > >
> > > > Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > > > ---
> > >
> > > Thanks for keeping at this. Setting up the APE6 board for further tests
> > > was painful, I understood that.
> > >
> > > Since you lost the cover-letter from the last series, I think it should
> > > be mentioned that this fixes a clock imbalance problem (at least on
> > > Gen3).
> > >
> > > For the APE6 tests, we need to wait until Geert comes back. I surely
> > > would like his input. And Yamada-san's, too, to make sure his platform
> > > also benefits.
> >
> > Thanks, but I still see a clock imbalances in /sys/kernel/debug/clk/clk_summary
> > when comparing before/after s2ram.
> >
> > On ape6evm:
> >
> > -   mmcif0   2   2   0   100000000   0     0  50000
> > +   mmcif0   1   1   0   100000000   0     0  50000
>
> This is unrelated to this patch, this clock is handled by the sh_mmcif
> driver. I get the same diff of the mmcif0 clock with a suspend cycle
> even if i do not include the renesas_sdhi_* drivers in the system.

OK.

> I had a quick look at the issue and it's related to that the MCC core do
> not call MMC_POWER_UP after suspend while it do call it during boot. Why
> it does so I'm not sure. Also if I mock convert sh_mmcif to require PM
> the imbalance is gone which perplexes me a bit and wonder if I converted
> it wrong somehow.

Weird... To be investigated further?

> > On r8a77965/salvator-xs:
> >
> > -   s0d3   1   2   0   266240000   0     0  50000
> > +   s0d3   2   2   0   266240000   0     0  50000
> >
> > -   sys-dmac0   0   1   0   266240000   0     0  50000
> > +   sys-dmac0   1   1   0   266240000   0     0  50000
>
> Even these are unrelated to this patch. If I test without renesas_sdhi_*
> driver in the system I get the same clock differences, in fact I get one
> more for sys-dmac1 (both with and without the shdi drivers).
>
> -    s0d3                  2        6        0   266240000          0     0  50000
> +    s0d3                  4        6        0   266240000          0     0  50000
>
> -       sys-dmac0          0        1        0   266240000          0     0  50000
> +       sys-dmac0          1        1        0   266240000          0     0  50000
>
> -       sys-dmac1          0        1        0   266240000          0     0  50000
> +       sys-dmac1          1        1        0   266240000          0     0  50000

Please ignore. I must have misread "s0d3" as "sd3" ;-)

> I have not investigate this further as I wish to make sens of this patch
> first ;-) Would you agree that with this information we should move
> forward with this patch as it solves the issue for the sdhi clocks on
> all effected SoCs ?

Yes please, and thanks again!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds